<p>My D often took 20 units but that load included 2 2-unit courses. The killer about the 2 unit courses isn’t the work load per se but just the amount of <em>time</em> the courses gobble up, time that can’t be used for other things, like your other classes or sleeping. Taking a load of 5 4-unit courses is not something I’d recommend for all but the most masochistic and sleep-immune student.</p>
<p>As for taking multiple languages, I suppose it’s possible but only if you don’t care about your GPA. I heard more “it killed my GPA” stories about languages than any other group of courses, including English and Math.</p>